Platen-operating mechanism



Nov. 16, 1937. A. T. GARDNER PLATEN OPERATING MECHANISM Filed Oct. 7, 1936 Patented Nov. 16, 1937 UNITED STATES PATENT OFFICE PLATEN-OPERATIN G MECHANISM Application October 7, 1936, Serial No. 104,506 In Great Britain November 4, 1935 3 Claims.

' This invention relates to platen operating mechanism for typewriting and like machines and more particularly when used with special forms of stationery, the supply of which is in 5 long continuous lengths.

It is frequently necessary, when operating a typewriter and like machines, particularly when utilizing a substantially continuous supply of stationery, which has for example, two or more sheets with interleaved carbon paper, to rotate the platen through one or more complete revolutions in one operation.

Known constructions of machines of this nature are provided with platen twirlers or knobs at each end of the platen for rotating the platen to the desired position. These platen twirlers, whilst being eminently suitable for partial rotation of the platen, do not readily lend themselves with facility for one or more complete revoluno tions of the platen.

Moreover, the size of the platen twirlers is limited to a certain extent by reason of the fact that it is necessary for them to travel with the carriage of the machine so that they must not obtrude or interfere with any parts of the machine itself during travel.

There have been proposals for mechanism, known as line-spacing mechanism, which give a step by step movement of the platen, usually through the agency of a pawl and ratchet device in association with the platen shaft. The principal object of the present invention however, is to provide a cheap and efficient device whereby a platen can be rotated speedily through one or more complete revolutions as opposed to a step by step movement. Another object of the present invention is to provide an operating mechanism for a typewriter which does not interfere with the normal working of the machine.

According to the present invention, a platen operating device comprises a lever having a handle at one end which lever is normally held in a position along the axis of the platen shaft so that it does not obtrude or interfere with the normal working of the machine during travel or otherwise, and is capable of being brought into an operative position for rotating the platen, said lever when in its operative position acting about the axis of the platen shaft.

Preferably, the lever is pivotally mounted on a member either formed by an extension of the platen shaft itself or a member attached thereto and is normally held in a position along the axis 55 of the platen shaft and when moved into its operative position lies at an angle of approximately 90 to the said axis.

A device embodying the invention and suitable for attaching to a platen shaft of an existing typewriter is hereinafter described and shown in the accompanying drawing wherein- Figure 1 is a section view showing the handle in its normal position and Figure 2 is a side elevation showing the handle in its operative position. 10

Referring to the drawing, a platen a has passing therethrough in known manner a shaft b which is customarily and hereinafter referred to as the platen shaft. The device according to the invention, comprises a sleeve portion c, which 15 is adapted to receive the end of the platen shaft 1), the sleeve portion being secured thereon by means of a grub screw d. The platen twirler or knob e is of known construction.

The other end of the sleeve portion 0, that is to say, the end remote from the platen shaft b is enlarged and provided with a slot Pivotally mounted on a pin g is one end of a lever h, the other end of which is provided with a rotat able knob i.

As shown in Figure 1, the lever h normally lies along the axis of the platen shaft shown by the line AA and is held in this position through the agency of a coil-spring 7' one end k of which bears against the wall of the slot and the other 30 arm I of which bears against the underside of the lever h and lies in a slot cut therein or alternatively, may be housed in an aperture drilled through the centre of the lever h.

Accordingly, the movement of the carriage of a machine having such a platen operating device is effected in a normal manner, since there is no projection which can interefere with other parts of the typewriter.

To operate the device, 1. e. to revolve the plat- 40 en, it is only necessary for the operator to grip the knob z and move the arm 72 against the action of the spring is so that the handle assumes the position shown by the line 3-3 in Figure 2. On releasing pressure on the knob i, the lever h 45 is automatically returned to the position shown in Figure 1, through the agency of the spring 70.

The above example is, of course, only one of the many methods according to which the present invention can be effected and it will, of 5 course, be obvious to anyone skilled in the art, that there are a number of methods of arranging the lever 71. so that it is normally held in such a position along the axis of the platen shaft that it does not obtrude or interfere with the normal working of the typewriter, which is capable of being brought into an operative position for rotating the platen and which automatically restores the lever to its normal position the moment it is not required.

'What is claimed is:-

1. In a machine of the character described, a platen, a shaft carrying said platen, mechanism for operating said platen, comprising a lever, one

end of said lever being pivotally connected to said platen shaft, a handle at the other end of said lever, said lever being normally held'in a position along the axis of theplaten shaft so that it does not interfere with the normal travel of the platen across the machine, the said lever being capable of being brought into a position for rotating said platen, said lever acting about the axis of said platen shaft.

2. In a machine of the character described, a

of said lever, said lever being normally held in a position along the axis of the platen shaft so that it does not interfere with the normal travel of the platen across the machine, the said lever being capable of being brought into a position approximately at right-angles to the said platen shaft for rotating said platen, said lever acting about the axis of said platen shaft.

3. In a machine of the character described, a platen, a shaft carrying said platen, mechanism for operating said platen, comprising a lever, an 'extensionjon' said platen shaft, one end of said lever being pivotally connected to said extension, a handle at theother end of said lever, said lever being'normally held in a position along the axis of the platen shaft so that it does not interfere with the normal travel of the platen across the machine, the said lever being capable of being brought into a position approximately at rightangles to said platen shaft for rotating said platen, said lever operating about the axis of said platen shaft.

' ALBERT THOMAS GARDNER. 

